Apparatus and method for preparing concrete in mixers



A ril 21,- 1936.

R. B. GAGE APPARATUS AND METHOD FOR PREPARING CONCRETE IN MIXERS FiledDec. 14, 1952 2 Sheetg-Sheet 1 April 21,1936. R B A E 2,038,276

APPARATUS AND METHOD FOR PREPARING CONCRETE IN MIXERS Filed Dec. 14,19.52 2 Sheets-Sheet 2' Patented Apr. 21, 1936 PA US AND lua'rnon FORPREPARING voca ists IN Mim cs Robert B. Gage, 'renton, N. J., as signorof onehalf to' Robert wi'Bailyf h rnl c iien Dsqemlwr 4 93 Maserat -axAn object of my present invention is to provide a methodfor preparingconcrete in cp-ncrete nn' xers', the method being comparatively simpleyet ing drum of a concretemixer, such vibrations being imparted onlywhen the skip is dischargin'g position and only when concrete is beingprepared or discharged from the mixing drum;

In this connection, the imparting of vibrations or the "energizing of avibrator which is attached to the skip or the mixing drum is one of theprimary features'of my invention. Iam aware that heretofore blows havebeen imparted to skips and mixing drums, such blowsbeingmechanicallyproduced in various ways. The application of a vibratorto the skip one ,tothe mixing drum, however, producesa constrictionin'which the skip and mixing are actually vibrated so as to vibratethecoat'ing "of'cerrient especially, which tends to stick tothe su-rfathe skip and drum and thus loosen'them'during" the discharging processof th 'skip into the and from the interior surfaces of the" dru'mduringthe preparation of the concrete, or"'while d ischarging .into achute leading from the' drum.

Stillafurther object .is to provide 'an 'appa'ratus in which vibratorsare applied to the'sk'ip andniixing drum of a ,ncrete mixer with novel:1 means being providedfor ener izngthe vibrators.

uring p pa ati n dis harg n mperiods. 7

With these and other objects in view my invention consists in the stepsotthe proce sshereinafter outlined and in the construction, arrangevDarts th cement, the :lower en'dbeing closed by a plate mentfandcombination of the var'i'o apparatus, wherebythe'objectscontemplated reattained,as hereinaftenmore":fully fsetffo li',

pointed out inmy claimsandillustrated) the" accompanying drawings, inwhichfthe al us is'disclosei' Oii'the drawings, Figure 1 is a plan view0 a eonc'r'etemixer with my"apparatus applied thereto forpracticing'th'e' process which I' will ..,i a, r.

Figure 2 is a side elevation of the same, some parts being broken awayto better illustrate the Figure 3 a side elevation with parts of themixing drum and skip broken away and shown in section to illustrate thevibrators-applied to the concrete mixer in accordance with my innt sm: rFigure fl-is an enlarged sectional view on the line (l ;4of-;Figure 3showing a collector ring arrangement- Figure 5 is a side elevationsimilar to a part of Figure 2 showing a modified construction in whichpneumatically operated rather than electrically operated vibrator meansis used.

lijigure 6 is an enlarged sectional view on the line 15- 5 of: Figure 5-showing the pneumatic vi- Figure 7 is an enlarged sectional view on theline w'l-- 1 of Figure ,5 showing an automatic air connection for thepneumatic vibrator; and

figure 8 is a diagram of electric connections of ,the apparatus. n 4

Qnthe accompanying drawings, I have showna cgncleete mixer Amore or lessdiagrammatically sincejthe details thereof do not'form any partofmypresent invention and intact; do 'notnaifect it except 'aspartsofthe-mixerare described in detail and given reference numeralshereinafter. The concrete" mixer A is ordinarily provided with a mixingdrum [0 of rotatable-character and having mixing-blades l 2-t5herein'whereby rotation ofthe drum will tumble and mix cement and aggregate forforming'concrete thereof.

Pivoted on a shaft I4, is an armlfi to the outer end of whichi's'securedra skip l 8 to receive cement and aggregate. ;The skip is"adapted to be swung to the;dott,e, d' line position of'Figure 2 fordumping the'cement and aggregate into the drum I 0.

Within .the'fskip thereiis-provided a compartment',,20; in"-which mixingblades 2 operate to.

V hydrate cement, or" in other words, to mix cement'and watero beforeintroducing such hydrated cement intd'theo-mixing' drum lfl'along withaggregatein'the major portion of the skip I8;

A discharge chute 24 is provided for hydrated 26; Thej'plate 16 hasanextension 28 adapted to engage the mixing 'fdrum lfl or any desiredprojection-iand ope'mthe plate 26 sothat the hy- -drate'dcementcanflowinto the mixing drum l0.

of concrete build up successive coatings of the ocment until the coatingis quite heavy and during one of the discharging operations of the skip,it discharges into the mixing drum. This makes that particular batch ofconcrete richer than the others because of the additional cement and theother batches are deficient because of this cement having been takenfrom them in building up the coating on the surface of the skip.

Likewise, coatings are built up in the drum I61 and occasionally breakloose making an extra rich and unevenly mixed batch, especially if thecement breaks loose just before discharging the concrete from the mixingdrum.

Such uneven mixtures of cement are detri mental to the quality of aslabof concrete being; laid and especially when the coating from theskip and the coating from the mixing drum combine in a single batch ofconcrete, an exceptionally rich batch is produced which isproportionally:

much richer than the ordinary run of batches. All of this is undesirableand I have found that by the use of vibrators as I will describe, thesedifficulties are overcome and all batches of concrete from the mixer areuniform. 1

I have also devised a means whereby the mixture is more uniformthroughout, such means consisting of the hydrator, indicated by thereference numerals 20,22, 24, 26 and 28, which is attached to the skipand accordingly vibrated with theskip to effectively expel all thehydrated cement therefrom during a skip dumping operation.

In Figures 1, 2 and 3, I have shown a vibrator B for the skip H3. Thevibrator B may consist of a motor 30 having an off-center weight 32 onthe shaft thereof whereby rotation of the motor shaft will producevibration because of the unbalanced centrifugal force of the eccentricweight 32 during rotation thereof. 1

It is not necessary to vibrate the skip l8 except when it is indischarging position. I provide means for automatically energizing themotor 30 at only the discharging position of the skip, such meansconsisting of a stationary contact 34 on the frame of the mixer A and amovable contact thus establishing the electric circuit tocause vibrationof the skip l8.

This vibration is not to be confused with hammering which knocks thecement loose, vibration, on the other hand, being imparted to the skipfor causing it to vibrate andthus free the coating of cement therefromdue to the inertia of the coating tending to cause it to remain in oneposition while the vibration of the. skip tends to move it with thevibratory movement. This causes a loosening of the coating and causes itto now more freely into the mixing .drum [0 while the vibrator isoperating.

The plate 26 for the hydrated cement is moved to open position, as shownby dotted lines in Figure 3, when'the skipis in discharging position.

This prevents the hydrated cement from flowing from the chute 24 beforethe skip isin position for it to flow into the mixing drum. 'I'hedischarge end of the chute 24 is quitesmall so as to reduce the flow ofthe hydrated cement sufiicientlyto cause flow thereof into the mixingdrum during three or four rotations of the drum. This evenly distributesthe hydrated cement throughout the aggregate flowing into the drum fromthe skip.

The vibrato-r B being attached to the skip l8 also vibrates thecontainer for the hydrated cement so as to effectively discharge itcompletely instead of leaving any coating for subsequent accidentaldjscharge into later batches of concrete with the consequent unevennessof quality throughout the batches.

For the mixing drum I6, I provide a vibrator C consisting of a motor 38and an eccentric weight 40.- These are housed in a housing 42 secured bystruts 44 or the like to the interior or exterior of the mixing drum l6.

- A'collector ring assembly D is shown in Figure 4. Where one side ofthe motor 38 is grounded, itis merely necessary to provide a contact 48for conducting electricity to the motor. Where a two wire system isused, a collector ring 50 is also provided with which a stationarycontact 52 coacts. The contacts 48 and'52 maybe carbonbrushes-spring'pressed to maintain good contact as illustrated in Figure4.

Means in the form of a push button 54 is provided for automaticallyoperating or' energizing the vibrator C. The push button 54 is locatedso that a projection 56 of a discharge chute 58 is engageable therewithwhen the discharge chute is l in discharging position. Thus only whenconcrete is being discharged from the drum ID the vibrator C operates,should its operation be, un-

necessary in the intervening periods of time.

Sometimes it is necessary to have the vibrator C operate in theintervening periods of timebecause there is a tendency for the concreteto build up aiilm on the drum in excess of that which can be vibratedloose during the discharging periods only.- I have therefore provided aswitch 55a which shunts the switch 54 and thus causes continuousoperation of the vibrator C. After the excessive film of concrete hasbeen removed, then the switch 55: can be opened whereafter automaticoperation of the vibrator C will occur i only during the dischargingperiods or when the chute 58 is in discharging position.

The push button 54 is connected with a conduit 51 which in turn, throughthe medium of an outlet box 55, is connected with a conduit 53. The

conduit 53 leads to the collector ring assembly D. A conduiti59 isprovided for convenience in connecting the electric system of thevibrators A and B to a source of current supply.

.In Figures 5, Sand 7, I have shown a pneumatic vibrator B. It isdesigned to take the place of the vibrator B and comprises a cylinder 6|having a reciprocable piston 60 therein. This is of the ordinarypneumatic hammer type and the-parts are so designed that the piston 66reciprocates rapidly within the cylinder 6| to produce vibrations.

The ordinary means for energizing the vibrator B may consist of acompressed air supply pipe 62 having ahead 64 to coact with a head 66 ofa pipe 68; The pipe 68 and the head 66 are carried by the skip I8 whilethe head 64 is mounted stationarily. In the skip discharging position,the head 66 enters the head 64 as shown in Figure '7 and, engages asealing cup leather 10 against the action of a spring 12.

At the same time a j valve 14 is automatically opened for admittingcompressed air to the vibrator]? and thereby.

operating it. The valve 14 is automatically reclosed when the head 66 iswithdrawn from the head 64.

A vibrator C of similar construction to the one shown in Figure 6 may bemounted in the drum I0 and connected by a rotary air tight connection Dand a conduit 53a with a valve 54a. Compressed air is supplied to thevalve 54a from a conduit 59a. The valve 54a corresponds to the switch 54and is normally closed but opened upon engagement of the projection 56of the chute 58 therewith. If it is desired to continuously operate thevibrator C", a valve 541) may be opened for continuously supplyingcompressed air thereto rather than supplying it only when the valve 54ais opened.

I have shown two forms of vibrators, one operated by electricity andanother by compressed air. These or other types of devices which willimpart actual vibrations to the skip and mixing drum may be used inpracticing my process. Steps of the process may be changed and changesin the construction and arrangement of the parts of the apparatus may bemade without departing from the real spirit and purpose of my invention.Therefore, I intend to cover by my claims such modified methods andforms of structureor mechanical equivalents which may be reasonablyincluded within their scope.

I claim as my invention:

1. An apparatus for preparing concrete comprising a mixing drum, a skipmovable from a supine receiving position to an upstanding dischargingposition, an electrically operated high frequency vibrator attached tosaid skip and adapted when energized to vibrate said skip sufficientlyto render its contents fiowable therefrom and circuit closing meansoperable by said skip to energize said vibrator when said skip is indischarging position.

2. An apparatus for preparing concrete comprising a mixing drum, a skipmovable from a supine receiving position to an upstanding dischargingposition, a pneumatically operated high frequency vibrator on said skipand adapted when operable to vibrate said skip to render its contentsflowable therefrom and valve means operable by said skip to energizesaid pneumatic vibrator when said skip is in discharging position.

3. An apparatus for preparing concrete comprising a mixing drum, amovable discharge chute therefor, a vibrator on said drum, means engagedby said discharge chute when in discharging position to operate saidvibrator to cause flowability of concrete in said drum and means torender said last means ineffective and to continuously operate saidvibrator.

4. An apparatus for preparing concrete comprising a mixing drum, amovable discharge chute therefor, an electrically operated highfrequency vibrator on said mixing drum and circuit closing meansoperable by said discharge chute to energize said vibrator eithercontinuously or when said discharge chute is in discharging position tocause flowability of concrete in said drum.

5. An apparatus for preparing concrete comprising a mixing drum, amovable discharge chute therefor, a pneumatically operated highfrequency vibrator on said mixing drum and valve means operable by saiddischarge chute to energize said vibrator when said discharge chute isin discharging position to cause flowability of concrete in said drum.

6. An apparatus for preparing concrete comprising a mixing drum, a skipmovable from a supine receiving position to an upstanding dischargingposition, a vibrator on said skip, a vibrator on said mixing drum, meansenergized by said skip when moved to discharging position to operate thevibrator thereon at a frequency sufficiently high enough to causeflowability of concrete in said skip and means to operate the vibratoron said mixing drum to cause flowability of concrete in said drum.

7. An apparatus for preparing concrete comprising a mixing drum, a skipmovable from receiving position to discharging position relative to saidmixing drum, an electrically operated high frequency vibrator on saidskip, an electrically operated high frequency vibrator on said mixingdrum, circuit closing means operable by said skip to energize saidvibrator on said skip when said skip is in discharging position to causefiowability of concrete in said skip and circuit closing means operableto energize said vibrator on said mixing drum to cause flowability ofconcrete in said drum.

8. An apparatus for preparing concrete comprising a mixing drum, a skipmovable from receiving position to discharging position relative to saidmixing drum, a pneumatically operated high frequency vibrator on saidskip, a pneumatically operated high frequency viabrator on said mixingdrum, valve means operable by said skip to energize said vibrator onsaid skip when it is in discharging position to cause flowability ofconcrete in said skip and valve means operable to energize said vibratoron said mixing drum to cause fiowability of concrete in said drum.

ROBERT B. GAGE.

